# Scaling and spatial intermittency of thermal dissipation in turbulent convection

## TL;DR

This paper derives scaling laws for thermal dissipation in turbulent convection, revealing boundary layer dominance and suppression of bulk dissipation, with numerical simulations confirming stretched exponential distributions.

## Contribution

It introduces new scaling relations for thermal dissipation in turbulent convection at various Prandtl numbers, supported by direct numerical simulations.

## Key findings

- Boundary layer dissipation dominates over bulk dissipation.
- Thermal dissipation in the bulk is suppressed compared to passive scalar dissipation.
- Dissipation rate distributions follow stretched exponential functions.

## Abstract

We derive scaling relations for the thermal dissipation rate in the bulk and in the boundary layers for moderate and large Prandtl number (Pr) convection. Using direct numerical simulations of Rayleigh-B\'{e}nard convection, we show that the thermal dissipation in the bulk is suppressed compared to passive scalar dissipation. The suppression is stronger for large Pr. We further show that the dissipation in the boundary layers dominates that in the bulk for both moderate and large Pr. The probability distribution functions of thermal dissipation rate, both in the bulk and in the boundary layers, are stretched exponential, similar to passive scalar dissipation.